Following the detailed Green Feasibility study of this Grade I Listed Building in the heart of London’s Embassy quarter Nick Baker Architects were commissioned to carry out a full extensive external refurbishment of the fabric of this 200 year old building. By adding double glazing, secondary glazing, insulation and draught stripping it has been possible to significantly reduce the heat loss from this traditional building and the subsequent annual maintenance and energy costs. Permission was granted to install the revolutionary ‘spacia’ glazing panels with a 0.5mm vacuum air gap to achieve U values of 0.8 W/m2K. Additional items such as photovoltaic panels and solar thermal hot water heating have been added to provide alternative energy sources to a fully overhauled services project for the building. The complex task of obtaining statutory approvals from English Heritage, Westminster City Council and landlords, The Grosvenor Estate, has been dealt with effectively and efficiently to enable the Embassy to concentrate on their official operational tasks in the UK.